Improvement in governors for furnace-doors



A c. unncnoss.

Bovernors for Furnace-Hours.

P10148132. Patented March 3.1874,

' UNITED STATES PAIEnEQEE C ALVIN O. NORCROSS, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN GOVERNORS FOR FURNACE-DOORS.

SpccTfi alion forming part of Letters Patent No. 145 132, dated March 3,1874 application filed January To all whom it may concern:

Be it known that I, ALVIN O. Noncnpss, of Boston, in the county ofSuffolk and 'State of Massachusetts, have invented a new and ImprovedAutomatic Governor for Hot-Air Furnaces, of which the following is aspecification:

The invention consists in combining, with the ordinary means for openingand closing a furnace-damper by expansion and contraction of a metallicbar, certain means whereby the adjustment may be obtained, ashereinafter described and claimed.

Figure 1 is a side elevation, partly in section; Fig. 2, a top view;Fig. 3, a front elevation.

A represents the expansible bar, which acts through a head, 0, and bymeans of an endpointed rod, H, 011 the lever 1),pivoted at I, to operatethe furnace-damper. The head 0 is provided with a spring, K, that actson a r different side of the fulcrum of lever D, and tends to open thedamper to the prescribed known to the public. I place, inside of the barF, so as to bear directly upon the rod H, or an intermediate plate, N,and at the top insert a base-piece, B, on which 'is a dial, whereon iscentered an adjusting-screw, G, having a pointer-head, M. The expanderA, of course, acts in the usual way to close the damper more and more asthe heat intensifies, while by means of my device added thereto, theexact opening of the damper is adjusted at first, and before the furnaceis heated up or afterward, the degree of adjustment being plainlyvisible on the dial-plate.

I claim The combination, with expander A, rod H, and lever D, of thenon-expansible bar F, pointer-headed screw G M, and dial-base B, as andfor the purpose described.

ALVIN O. NOROROSS.

YVitnesses A. P. THAYER, ALEX. F. ROBERTS.

limit. Substantially, these devices are well hollow expansible bar A,the non-expansible

